Voltage setting of adapter

ABSTRACT

Embodiments herein relate to setting a voltage of an adapter ( 100, 200 ). In an embodiment, the adapter is to measure a current output by the adapter, compare the measured current at the adapter to a first current and to output a DC voltage. The adapter is to set a level of the DC voltage output by the adapter based on the comparison.

BACKGROUND

Traditionally, different types of notebook computers used different sizeand/or types of direct current (DC) plugs. Therefore, connecting a DCsource, such as an alternating current (AC) adapter, to the wrongnotebook computer was not possible because a connector of the DC sourcewould be physically incapable of mating to the DC plug of the notebook.

However, newer notebook computers now have the same type of DC plugsdespite having different power requirements. As a result, the DC sourcemay be connected to the wrong notebook computer. For example, thenotebook computer may attempt to draw power beyond a capacity of the DCsource. Thus, the notebook computer and/or DC source may malfunction.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description references the drawings, wherein:

FIG. 1 is a block diagram of an example adapter;

FIG. 2 is a block diagram of another example adapter;

FIG. 3 is a block diagram of an example system including the adapter ofFIG. 1;

FIG. 4 is a more detailed example block diagram of the portable deviceof FIG. 3;

FIG. 5 is another more detailed example block diagram of the portabledevice of FIG. 3;

FIG. 6 is a flowchart of an example method for varying a voltage at theadapter; and

FIG. 7 is a flowchart of an example method for varying a power drawn atthe portable device.

DETAILED DESCRIPTION

Specific details are given in the following description to provide athorough understanding of embodiments. However, it will be understood byone of ordinary skill in the art that embodiments may be practicedwithout these specific details. For example, systems may be shown inblock diagrams in order not to obscure embodiments in unnecessarydetail. In other instances, weft-known processes, structures andtechniques may be shown without unnecessary detail in order to avoidobscuring embodiments.

Embodiments provide a generally low cost and reliable method and/ordevice to signal the power capacity of the AC adapter. For example,embodiments may include an adapter to dynamically lower its output DCvoltage to a portable device when a threshold power capacity that isless than a maximum power capacity of the adapter is reached. Theportable device may then lower its power consumption before the maximumpower capacity of the adapter is reached. As a result, the portabledevice and/or adapter may prevent any malfunctions or damage caused bythe portable device attempting to exceed the maximum power capacity ofthe adapter.

In addition, embodiments of the adapter are able to signal to theportable device that the threshold capacity is reached without anyadditional connections therebetween. Thus, embodiments may bemanufactured with little or no additional manufacturing costs orcomplexity.

FIG. 1 is a block diagram of an example adapter 100. The adapter 100 maybe a type of device that supplies electrical energy to one or moreelectric loads. Moreover, the adapter 100 may convert energy from one totype to another type. For example, the adapter may convert anAlternating Current (AC) voltage source into a Direct Current (DC)voltage source. In the embodiment of FIG. 1, the adapter 100 includes aconverter 110, an adapter meter 120, a comparator 130, and a switch 140.The adapter 100 is to receive an AC voltage from an external AC source160, such as a wall outlet providing AC voltage at 120 Volts (V), 60Hertz (Hz) or 220 V, 50 Hz. However, embodiments of the AC source 160are not limited to a wall outlet, and may also include other types of ACsources as well.

The converter 110 is to receive the AC voltage and to output a DCvoltage via a variable voltage source 112 through a first connection.The converter 110 may include a transformer (not shown) to transform theAC voltage into the DC voltage. The DC voltage is to be output via thevariable voltage source 112, with the variable voltage source 112 tovary the DC voltage output in response to a signal output by thecomparator 130, as explained in greater detail below.

The adapter meter 120 is to measure a current output by the adapter 100at the first connection and output the measured current to thecomparator 130. The adapter meter 120 may, for example, be an ammeter.

The comparator 130 is to compare the measured current to a firstthreshold current and output a comparison signal to the variable voltagesource 112 and the switch 140, based on the comparison. Generally, thecomparator 130 may be an electrical device to compare two or morevoltages or currents and to base its output on the comparison.

In FIG. 1, the first threshold current is to indicate a percentage of apower capacity of the adapter 100 that is less than an entirety of thepower capacity of the of adapter 100, such as 90% of the adapter's 100power capacity. The power capacity may indicate a maximum power outputcapability of the adapter 100. In FIG. 1, the comparator 130 may outputthe comparison signal at a first voltage if the measured current is lessthan the first current and output the comparison signal at a secondvoltage different than the first voltage if the measured current isgreater than or equal to the first current.

The output of the comparator 130, such as the first or second voltage isoutput to the variable voltage source 112 of the converter 110 to varythe DC voltage, where the variable voltage source 112 is to vary the DCvoltage output based on a voltage level received from the comparator130. For example, the variable voltage source 112 may set the DC voltageto a lower voltage, such as 10 V, upon receiving the first voltage, andmay set the DC voltage to a higher voltage, such as 20 V, upon receivingthe second voltage. While the comparator 130 is configured to increasethe level of the DC voltage output to by the converter 110 when themeasured current is greater than or equal to the first current,embodiments are not limited thereto. For example, in another embodiment,the comparator 130 may be configured to decrease the level of the DCvoltage output to by the converter 110 when the measured current isgreater than or equal to the first current.

The output of the comparator 130 is also output to the switch 140. Theswitch 140 may be any type of electrical, mechanical orelectromechanical device capable of switching between two or moreelectrical contacts. The switch 140 is to select between a firstthreshold current and a second threshold current different than thefirst threshold current, based on the output of the comparator 130 andto output the selected current as the first current to the comparator130. The first and second threshold currents may, for example, bedetermined experimentally or set according to a manufacturer's or user'sspecifications.

For example, the first threshold current may be greater than the secondthreshold current, and the switch 140 may be initially set to thegreater threshold current, e.g. the first threshold current. Inembodiments, the first and second threshold currents may, for example,be 2 and 1 amps or 4 and 2 amps, respectively. In FIG. 1, the switch 140is to receive the comparison signal. If the comparison signal is at thefirst voltage, the switch 140 is to be set to the first thresholdcurrent and if the comparison signal is at the second voltage, theswitch 140 is to be set to the second threshold current.

Thus, in operation, if the measured current being output by the adapter100 at the first connection is greater than or equal to the firstcurrent, which is initially set as the first threshold current, thecomparator 130 will output the second voltage. Accordingly, theconverter 110 will increase the DC voltage output. Due to a constantpower being output from the adapter 100, the measured current will thendecrease and perhaps be lower than the first threshold current. Forexample, if the first current is 1.1 Amp (A), the measured current is 2A, and the initial voltage is 10 V, then the adapter 100 switching fromoutputting 10 V to 20 V, would result in the measured current droppingfrom 2 A to 1 A.

Thus, the first current is set to the second threshold current by theswitch 140 in response to receiving the second voltage, where the secondthreshold current will be lower than the measured current at the secondvoltage, e.g. less than 1 A. Hence, the comparator 130 will not outputthe first voltage again and thus lower back the DC voltage output by theconverter 110.

The first connection may represent a point of connection, such as a pin,tip or hole, to be connected to an external load, such as a portabledevice.

FIG. 2 is a block diagram of another example adapter 200. In thisembodiment, the adapter 200 is similar to the adapter 100 of FIG. 1,except the comparator 230 is to compare the measured current to aplurality of currents and each of the switches 240 are to switch betweenmore than two threshold currents for each of the currents. In addition,the comparator 230 is to output from between more than two voltages.

For example, the converter 110 is to set the DC voltage to a firstoutput voltage when the comparator 230 outputs the first voltage toindicate that the measured current is less than a first current of theplurality of currents by outputting the first voltage. The converter 110is to set the DC voltage to a second output voltage greater than thefirst output voltage when the comparator 230 outputs the second voltageto indicate that the measured current is greater than or equal to thefirst current and less than a second current, where the second currentis greater than the first current. The converter 110 is to set the DCvoltage to a third output voltage that is greater than the second outputvoltage when comparator 230 outputs a third voltage to indicate that themeasured current is greater than or equal to the second current.

The output of the comparator 230 is also input to the switches 240,where the switches 240 operate similarly to the switch 140 in FIG. 1.However, the switches 240 each select between three threshold currents,instead of two threshold currents. For example, the switches 240 mayrespectively be set to first and fourth threshold currents uponreceiving the first voltage. Also, the switches 240 may respectively beset to second and fifth threshold currents upon receiving the firstvoltage. In addition, the switches 240 may respectively be set to thirdand sixth threshold currents upon receiving the first voltage. The firstthrough third threshold currents may have progressively lower values andthe fourth through sixth threshold currents may have progressively lowervalues.

In FIG. 2, the first and second currents may relate to different powercapacities of the adapter 200. For example, the first threshold currentmay relate to a lower, such as 10%, of a maximum power capacity of theadapter and the second threshold current may relate to a higher, such as90%, of the maximum power capacity of the adapter. While FIG. 2 onlyshows the two threshold currents, embodiments may include more than twothreshold currents.

FIG. 3 is a block diagram of an example power system 300 including theadapter 100 of FIG. 1. However, embodiments may also include the adapter200 of FIG. 2 or other similar types of adapters. In this embodiment,the power system 300 includes the adapter 100 of FIG. 1 and a portabledevice 310 connected to the adapter 100 or 200. The portable device 310includes a load 320 to receive power through the first connection. Theload 320 may refer to power drawn by the components of the portabledevice 310, such as a battery, a processor, a display, a hard drive, acontroller, and the like of the portable device 310. The portable device310 is to vary the load 320 of the portable device 310 based on a changein the DC voltage output by the adapter 100 or 200 or received at theportable device 310 via the first connection, as will be explained ingreater detail below in FIGS. 4 and 5 below.

In FIG. 3, the power system 300 is shown to include the portable device310. Embodiments of the portable device 310 may include, for example, anotebook computer, a desktop computer, an all-in-one system, a slatecomputing device, a portable reading device, a wireless email device, amobile phone, and the like.

FIG. 4 is a more detailed example block diagram of the portable device310 of FIG. 3. In this embodiment, a portable device 410 includes theload 420. The load 420 includes a portable device meter 430, a voltagedetector 440 and a controller 450.

The voltage detector 440 is to detect a voltage received by the portabledevice 410 through the first connection and output the detected voltageto the controller 450. The voltage detector 440 may be any type ofdevice configured to measure an electrical potential difference betweentwo points in an electric circuit, such as a voltmeter.

The portable device meter 430 is to measure a current received by theportable device 410 through the first connection and to output themeasured current to the controller 450. The portable device meter 430may, for example, be an ammeter.

The controller 450 is to determine an amount to vary the load 420 basedon the current measured by the portable device meter 430 at least one ofduring and after a change in DC voltage detected by the voltage detector440, such as in increase in voltage from 10 V to 20 V. The controller450 may vary the load 420 of the portable device 410 by varying power toat least one of the battery, processor, display, hard drive and othercomponents included in the portable device 410. For example, thecontroller 450 may stop charging the battery, dim the display, or lowera clock frequency of the processor. Other components of the portabledevice 410 may also include, for example, the controller 450 or theportable device meter 430.

The controller 450 may be one or more central processing units (CPUs),semiconductor-based microprocessors, and/or other hardware devicessuitable for access and execution of instructions stored in amachine-readable storage medium (not shown) located internal or externalto the controller 450.

The machine-readable storage medium may be any electronic, magnetic,optical, or other physical storage device that contains or storesexecutable instructions. The machine-readable storage medium may storeone or more applications executable by the controller 450. In oneembodiment, the application may determine an amount to vary the load 420of the portable device 410 by limiting or disabling power to one or morecomponents, based on an amount of current received at the portabledevice 410 at least one of during and after the change in the DC voltagereceived at the portable device 410.

FIG. 5 is another more detailed example block diagram of the portabledevice 310 of FIG. 3. In this embodiment, portable device 510 of FIG. 5may be similar to the portable device 410 of FIG. 4, except that theportable device 510 does not include the portable device meter 430 ofFIG. 4. Instead, controller 550 may indirectly determine the currentbased on the voltage detected from the voltage detector 440 and thepower drawn by the load 520.

FIG. 6 is a flowchart of an example method 600 for adjusting adapterpower. Although execution of the method 600 is described below withreference to the adapter 100 of FIG. 1, the adapter 200 of FIG. 2 orother suitable components for execution of the method 600 will beapparent to those of skill in the art.

In the embodiment of FIG. 6, at block 610, the converter 110 of theadapter 100 outputs a DC voltage to the portable device 310 via thefirst connection. At block 620, the adapter meter 120 of the adapter 100senses a current output to the portable device 310 via the firstconnection. Then, at block 630, the comparator 130 of the adapter 100compares the sensed current to the first current, the first current toindicate a percentage of a power capacity of the adapter 100 that isless than an entirety of the power capacity of the of adapter 100.Lastly, at block 640, the converter 110 of the adapter 100 changes theDC voltage output to the portable device 310 based on the comparison,the portable device 310 is to vary a power drawn from the adapter 100based on the changed voltage.

FIG. 7 is a flowchart of an example method 700 for varying a power drawnat the portable device 310. Although execution of the method 700 isdescribed below with reference to the portable devices 410 and 510,other suitable devices for execution of the method 700 will be apparentto those of skill in the art. In the embodiment of FIG. 7, at block 710,the voltage detector 440 detects the DC voltage received at the portabledevices 410 or 510. Then, at block 720, the controller 550 or theportable device meter 430 detects a current received at the portabledevice 410 or 510 at least one of during and after the detecting the DCvoltage of block 710 detects a change in the DC voltage. Then, at block730, the controller 450 or 550 varies the load 420 or 520 of theportable device 410 or 510, based on the detected current at block 720,an amount to vary the load being based on a value of the detectedcurrent.

In one embodiment, the detecting the current at block 720 may includemeasuring the current received at the portable device 410 using, forexample the portable device meter 430. In another embodiment, thedetecting the current at block 720 may instead include determining thecurrent received at the portable device 510 based on the load 420 and DCvoltage received at the first connection of the portable device 510.

According to the foregoing, embodiments provide a generally low cost andreliable method and/or device to determine the power capacity of theadapter before a maximum power capacity of the adapter is reached. Forexample, the portable device computer may correspondingly lower itspower consumption before the maximum power capacity of the adapter isreached based on a value of a signal received from the adapter, withoutany additional connections therebetween.

We claim:
 1. An adapter, comprising: an adapter meter to measure acurrent output by the adapter at the first connection; a comparator tocompare the measured current at the adapter to a plurality of currents,the plurality of currents to indicate different percentages of a powercapacity of the adapter that is less than an entirety of the powercapacity of the of adapter; and a converter to receive an AC voltage andto output a DC voltage via the first connection, the converter to set alevel of the DC voltage output by the converter based on the comparison.2. The adapter of claim 1, wherein, the comparator is to set the DCvoltage to a first output voltage when the measured current is less thana first current of the plurality of currents, the comparator is to setthe DC voltage to a second output voltage greater than the first outputvoltage when the measured current is greater than or equal to the firstcurrent and less than a second current greater than the first current,and the comparator is to set the DC voltage to a third output voltagegreater than the second output voltage when the measured current isgreater than or equal to the second current.
 3. The adapter of claim 2,wherein the first threshold current relates to a first power capacity ofthe adapter and the second threshold current relates to a second powercapacity of the adapter, the second power capacity being a greaterpercentage of a maximum power capacity of the adapter than that of thefirst power capacity.
 4. The adapter of claim 1, further comprising: aplurality of switches, each of the switches to select between aplurality of threshold currents and to output one of the plurality ofthreshold currents, based on the comparison.
 5. A power system,comprising: an adapter including, an adapter meter to measure a currentoutput by the adapter at a first connection, a comparator to compare themeasured current at the adapter to a first threshold current, the firstthreshold current to indicate a percentage of a power capacity of theadapter that is less than an entirety of the power capacity of theadapter, and a converter to receive an AC voltage and to output a DCvoltage via the first connection, the converter to set a level of the DCvoltage output by the converter based on the comparison; and a portabledevice connected to the adapter and to vary a load of the portabledevice based on a change in the DC voltage received at the portabledevice.
 6. The system of claim 5, wherein the portable device is todetermine an amount to reduce the load of the portable device based on acurrent received at the portable device at least one of during and afterthe change in the DC voltage received at the portable device so that theentirety of the power capacity of the adapter is not reached.
 7. Thesystem of claim 6, wherein the portable device includes, a portabledevice meter to measure the current received by the portable device, anda controller to determine an amount to vary the load based on a value ofthe current measured by the portable device meter at least one of duringand after the change in the DC voltage received at the portable device.8. The system of claim 6, wherein the portable device is to determinethe current received based on the load and the DC voltage received atthe portable device.
 9. The system of claim 5, wherein the portabledevice includes, a voltage detector to detect a voltage received by theportable device, and a controller to vary the load based on the changein the DC voltage received at the portable device.
 10. The system ofclaim 9, wherein the controller is to vary the load of the portabledevice by varying power to at least one of a battery, processor, displayand hard drive included in the portable device.
 11. The system of claim5, wherein the converter is to increase the level of the DC voltageoutput when the comparator determines the measured current is greaterthan the first threshold current.
 12. A method for setting adaptervoltage, comprising: outputting, at an adapter, a DC voltage to aportable device; sensing, at the adapter, a current output to theportable device; comparing, at the adapter, the sensed current to afirst current, the first current to indicate a percentage of a powercapacity of the adapter that is less than an entirety of the powercapacity of the of adapter; and changing, at the adapter, the DC voltageoutput to the portable device based on the comparison, the portabledevice to vary a power drawn from the adapter based on the changedvoltage.
 13. The method of claim 12, further comprising: detecting theDC voltage received at the portable device; detecting a current receivedat the portable device at least one of during and after the detectingthe DC voltage detects a change in the DC voltage; and varying a load ofthe portable device based on the detected current, an amount to vary theload being based on a value of the detected current.
 14. The method ofclaim 13, wherein the detecting the current received includes measuringthe current received at the portable device.
 15. The method of claim 13,the detecting the current received detects the current based on the loadand the DC voltage received at the portable device.